How to Figure the Amount of Concrete Block Required for a Home

Measure the overall length and height of the proposed concrete block wall. For a larger project, measure the length and height of each individual wall you plan to build and combine the totals to determine the aggregate wall length and average height.

Multiply the length times the height measurement of the wall to define the area of the wall in square feet.

Divide the total square feet of wall area by .89 to define the number of standard concrete blocks needed for the wall. The outside, or "face," surface of a common 8-inch by 8-inch by 16-inch concrete block is 128 square inches or .89 square feet. For example, a project has 520 linear feet of concrete block walls that average 4-feet tall. Multiply 520 by 4 to equal 2,080 square feet of wall area. The wall area is then divided by .89 for a total of 2,237 concrete blocks required for the walls.

Subtract for wall openings, if applicable. If you are estimating the concrete blocks for a home or addition with full height walls, you must deduct the areas for window and door openings from the wall area total. To complete this adjustment to the concrete block estimate, measure the height and width dimension of each opening in the wall. Multiply the two dimensions to define the area of the opening, then deduct that area from the wall area total.

Repeat Steps 1 through 4 for each length of wall for your project to determine the total quantity of concrete blocks needed.